青藏高原海螺沟冰川退缩区原生演替序列优势乔木氮磷化学计量及重吸收特征研究

Nitrogen and Phosphorus Stoichiometry and Resorption Characteristics of Dominant Trees in the Primary Succession Sequence of Hailuogou Glacier Retreat Area, Tibetan Plateau, China

  • 摘要: 以海螺沟冰川退缩区原生演替序列为对象,研究各演替阶段优势乔木氮(N)、磷(P)化学计量及重吸收效率特征。结果表明:优势乔木鲜叶及凋落叶N、P浓度随演替下降,且鲜叶的N∶P在整个演替序列中总体小于14 ,表明该演替序列优势乔木的生长主要受N元素限制;优势乔木N、P的重吸收效率在演替中期最高,表明植物较高的生长速率会增加其对养分的吸收利用效率;优势乔木N、P的重吸收效率与其生长速率呈正相关关系,而与土壤的N、P储量呈负相关关系,说明树木生长速率(需求)和土壤养分状况(供给)共同调节植物对养分的吸收模式;优势乔木N重吸收效率与其鲜叶N∶P呈正相关关系,表明植物对N的重吸收过程对维持其体内N∶P的平衡有着重要意义。研究结果有助于深入认识原生演替过程中植被对养分的利用机制,可为植被恢复提供理论依据。

     

    Abstract: Based on the primary succession of vegetation in the Hailuogou glacier retreat area, the characteristics of nitrogen(N) and phosphorus(P) stoichiometry and resorption efficiency of dominant trees in different succession stages were studied. The results showed that the N and P concentrations of fresh leaves and litters decreased with succession, and the N∶P of fresh leaves were less than 14 in the whole succession sequence, indicating that the growth of dominant trees in this succession sequence was mainly limited by N; the N and P resorption efficiency of dominant trees was the highest in the middle succession stage, indicating that higher plant growth rate would increase the efficiency of nutrient uptake and utilization; the resorption efficiency of N and P were positively correlated with their growth rate, and negatively correlated with soil N and P storage, indicating that the tree growth rate(demand) and soil nutrient status(supply) jointly regulated the nutrient uptake pattern of vegetation, the N resorption efficiency of dominant trees was positively correlated with the N∶P, indicating that the N resorption process of vegetation was important to maintain the balance of the N∶P. These results are helpful to deeply understand the nutrient utilization mechanism of vegetation in the process of primary succession, and provide theoretical basis for vegetation restoration.

     

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